CA1227075A - Colour varying reflector - Google Patents
Colour varying reflectorInfo
- Publication number
- CA1227075A CA1227075A CA000419300A CA419300A CA1227075A CA 1227075 A CA1227075 A CA 1227075A CA 000419300 A CA000419300 A CA 000419300A CA 419300 A CA419300 A CA 419300A CA 1227075 A CA1227075 A CA 1227075A
- Authority
- CA
- Canada
- Prior art keywords
- centre plane
- source
- reflective surfaces
- reflective
- reflector
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/12—Reflex reflectors
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Toys (AREA)
- Optical Elements Other Than Lenses (AREA)
Abstract
ABSTRACT
A reflector element which reflects different coloured signals back towards a light source, depending on which side of a centre plane the source is positioned, is disclosed. Reflective surfaces parallel to and equidistant from the imaginary centre plane face each other. A
third reflective surface is adjacent to, abuts, and is perpendicular to the other two reflective surfaces. Optionally, a fourth reflective surface is adjacent to, abuts, and is perpendicular to the other three reflective surfaces. Some or all of the reflective surfaces on one side of the centre plane are tinted, and some or all of the reflective surfaces on the other side of the centre plane may be differently tinted.
A reflector element which reflects different coloured signals back towards a light source, depending on which side of a centre plane the source is positioned, is disclosed. Reflective surfaces parallel to and equidistant from the imaginary centre plane face each other. A
third reflective surface is adjacent to, abuts, and is perpendicular to the other two reflective surfaces. Optionally, a fourth reflective surface is adjacent to, abuts, and is perpendicular to the other three reflective surfaces. Some or all of the reflective surfaces on one side of the centre plane are tinted, and some or all of the reflective surfaces on the other side of the centre plane may be differently tinted.
Description
7~;i This in-vention relates generally to reElectors, and par~icularly to a colour varying reflector, LOe. a reflector which returns different colours oE light to a light source depending on whether the source is on one ~ide or the other of a centre line or plane passing through the reflector.
It has long been recognized that there would be a use for such reflectors. There are obvious applications in, for example, highway and airport traEfic control. There are many situations in which it Ls useful to use a light source and such a reflector to receive an indication as to whether one i9 on one side or the other of a centre line or plane. Combining reflectors in different locatlons may also permit specific locations to be identlfied, through triangulation techniques. Reflectors may be ~ounted on a post, or embedded at road, run~ay or taxiway level, or positioned in any other suitable manner.
In the prior art, numerous attempts have been made to produce reflectors which return different signals to the source depending or~
the position of the source. In the simplest case, reflector units have been constructed consistlng of differently coloured reflectors on front and rear faces, t~us reflecting difEerent colours to sources opposed at 180 to each other from tha reflector. Such reflectors ha~e been used, for example, to provlde a red reflection from headlights of highway trafEic approaching ehe reflectors fro~ one direction and a green reflec~ion to traffLc approachlng from the other direction. Such reElectors obvlously cannot make fine angular distinctions, however, such as between sources of light which may be separated by as little ~s 45 or less, for e~ample.
Other attempt6 in the prior art have employed ~eans such a5 blinders pro~ectlng Ero~ the reflectLve surfaces towards the source, to -~ shade one portion or al1other oE the reflective elements depending on the angular position of the light source. The effectLYeness oE such
It has long been recognized that there would be a use for such reflectors. There are obvious applications in, for example, highway and airport traEfic control. There are many situations in which it Ls useful to use a light source and such a reflector to receive an indication as to whether one i9 on one side or the other of a centre line or plane. Combining reflectors in different locatlons may also permit specific locations to be identlfied, through triangulation techniques. Reflectors may be ~ounted on a post, or embedded at road, run~ay or taxiway level, or positioned in any other suitable manner.
In the prior art, numerous attempts have been made to produce reflectors which return different signals to the source depending or~
the position of the source. In the simplest case, reflector units have been constructed consistlng of differently coloured reflectors on front and rear faces, t~us reflecting difEerent colours to sources opposed at 180 to each other from tha reflector. Such reflectors ha~e been used, for example, to provlde a red reflection from headlights of highway trafEic approaching ehe reflectors fro~ one direction and a green reflec~ion to traffLc approachlng from the other direction. Such reElectors obvlously cannot make fine angular distinctions, however, such as between sources of light which may be separated by as little ~s 45 or less, for e~ample.
Other attempt6 in the prior art have employed ~eans such a5 blinders pro~ectlng Ero~ the reflectLve surfaces towards the source, to -~ shade one portion or al1other oE the reflective elements depending on the angular position of the light source. The effectLYeness oE such
-2-'7(~7~i units is obviously limited by the distance to whlch tlle bLi~ders pro~ect from the reElectors, and such projections are susceptLble to damage.
It is an object of the present lnvention to provide a colour varying reflector which is relatively simple and effective, and which offers advantages over colour varying reElectors in the prior art.
Thus in accordance with one aspect of the present invention there are provided first and second reflective surfaces facing each other in parallel, equidistant from and parallel to an imaginary centre plane.
A third reflective surface is positioned to face perpendicularly and abut both first and second reflective surfaces. At least one of the reflective surfaces is tinted on one side or the other of the centre plane.
In accordance with a further aspect of the invention, there is further provided a fourth reflective surface, positioned to face perpendicularly and abut each of the other reflective surfaces.
The inventlon will now be more particularly and clearly described with reference to drawings of the Lnvention, in which:
Fig. 1 is a plan view of a simple e~hodiment of the invention, illustrating the principle of the invention;
Fig~ 2 is an oblique drawing of the prefe~red e~bodLment of the invention, as viewed frcm the right of the centre plane.
Fig. 1 shows the simplest embodiment of the invention. A first plate 2 faces a second plate 6, the plates being paralLel to each other and equidistant from an imaginary centre plane C. A third plate 10 ls perpendlcular to the first and second plate. The in~ard-facing surfaces of the plate~ are coated with or supporc reflectiv~ surfac~s 4,8,1~ an(l 14. The reElective surfaces 12 or 14 a~e on opposlte ~ldes '~ of the centre plane. They may be separate sur~aces~ or merely aeparate
It is an object of the present lnvention to provide a colour varying reflector which is relatively simple and effective, and which offers advantages over colour varying reElectors in the prior art.
Thus in accordance with one aspect of the present invention there are provided first and second reflective surfaces facing each other in parallel, equidistant from and parallel to an imaginary centre plane.
A third reflective surface is positioned to face perpendicularly and abut both first and second reflective surfaces. At least one of the reflective surfaces is tinted on one side or the other of the centre plane.
In accordance with a further aspect of the invention, there is further provided a fourth reflective surface, positioned to face perpendicularly and abut each of the other reflective surfaces.
The inventlon will now be more particularly and clearly described with reference to drawings of the Lnvention, in which:
Fig. 1 is a plan view of a simple e~hodiment of the invention, illustrating the principle of the invention;
Fig~ 2 is an oblique drawing of the prefe~red e~bodLment of the invention, as viewed frcm the right of the centre plane.
Fig. 1 shows the simplest embodiment of the invention. A first plate 2 faces a second plate 6, the plates being paralLel to each other and equidistant from an imaginary centre plane C. A third plate 10 ls perpendlcular to the first and second plate. The in~ard-facing surfaces of the plate~ are coated with or supporc reflectiv~ surfac~s 4,8,1~ an(l 14. The reElective surfaces 12 or 14 a~e on opposlte ~ldes '~ of the centre plane. They may be separate sur~aces~ or merely aeparate
-3-7 ~
portions o~ a s:Lng1e surface.
The princlple of the invention may be understood by considerLng the paths of light beams fro~ a source S poæ:Lt:loned, for exampl.e, to the right of the centre p:Lane. I,ight beam 30 and any other light beams B from the source ~ i~pinging on reflect.lve surface 14 are reflected away from the source, as are some light beams such as light beam 31 impinging on reflective surface 12. However, light beams such as light beam 32 are reflected off ref1ective surface 12 to reflective surface 4 and thence back towards the source~ and the observer O positioned near the line of the light beam. It will be apparent that light can only be reflected back towards the source S if it reflects off both reflective surfaces 12 and 4, and not off re~lective surface 14.
Accordingly in the present lnvention one or preferably both of reflective surfaces 12 and 4 are tinted, so that light refl.ecti~g back to the source S becomes coloured. One or both of reflect.ive susfaces 8 ~` and 14 may al30 be tinted, but in a different colour so that different colours are reflected back to sources on different sides o~ the centre plane.
When the light source is positioned in the centre plane, then of course there i5 ~erely a str~ight reflection bac~ from reflectlve surfaces 12 and 14, resulting in a mixture of the tWQ colours ~eing perceived by the ob~er~er 0. However~ when the source and t-ne ob~rver move to one side or the other of the centre plane~ a coloured reflection ~ill be seen by the observar, isldicatlng which side of the plane the source and ob3erver are on.
The st~ength of the reflected signal relative to the source si~nal increases as the angle from the centse plane Lncreases, up to a ~axi~um at 45, since more of the llght re~lect~ off surface~ 12 and 4 rather : than o~f surface i2 only.
To ~inimi.ze the occurrence of excesslve internal reflection ~eyond ~' , C~7f-45 from the center plane, resulting Ln colour confuslon, the plates 2 and 4 should preEerably not extend from the plate 10 by a dLstallce greater than the cllstance between plates 2 and 6. General1y speaking, the reflector of the present invention Ls not lntended for optlmum performance beyond a 45 angle from the centre plane, although it may remain effective beyond 45 to varying degrees depending on the speciEic design.
It will be readily apparent eha~ the embodiment of Fig. 1 is only useful when the source and observer are ln the plane perpendicular to all of the reflective surfaces, i.e. in the paper plane of Fig. 1.
Otherwise, llght cannot be reflected back to the source because reElective surfaces 12 or 14 as the case may be will refLect the light upwardly or downwardly relative to the source. For many applications J
of course, this li~itation of this embodi~ent is not a problem.
In Lhe preferred e~bodi~ent, illustrated in FLg~ 2, this limitatlon is overcome by the addition of a fourth plate 16 with reflective surfaces 13 and 20. The first and second plates 2 and 6 are again parallel, plate lO i& perpendlcular to the~, and the fourth plate 16 i8 perpendicular to all three. As is well known and can be readily demonstrated, a light beam which reflects off, for example, ~urface 18 to surface 12 to surface 4 will then be reflected by surface 4 back towards the light beam source tn a manner directly analogous to that illustrated in Fig. 1. The reflector elel~ent ~s preferably oriented sueh that the source and observer are norrnally near the plane whlch is at 45 to the thlrd and fourth plates lO and 16.
Thus lf one or both or preferably all three o~ the surfaces 18, 12 and 4 are tinted, then such a light beam would produce a coloured signal to an observer positioned close to the llne of the light bea~.
In Fig. 2, the reElector element Ls ill~trated as it ~ould be seen from a viewpoint to the right of the centre plane, l.e. tha plane ~ ~'7~
parallel to and equidistant Erom reElectlve surfaces 4 and 8. It can be readily appreciated tllat some of the lLght directed towards the reflector from a source in line with the viewpoint would be reflected off surfaces 18, 12 and 4 (in any order) to produce a coLoured signal.
Part of the light would be reflected off only one or t~o of the surfaces, for example reflecting off surfaces 18 and 12 and then oEf to the left of the centre plane without contacting surface 4. None of the light which reflected off either or both of surfaces 14 and 20 would be reflected off surface 4 and back towards the source.
As Ln the case of the simple embodimetlt of Fig. 1, when the light source is positioned in the centre plane, there is simple reElection back towards the source, off suriaces 18 and 12 and off surfaces ~0 and 14, resultin~ in a mi~ture of colours being perceived. Mowever, moving the source and the observer away from the centre plane results in different coloured signals being retur~ed to the observer dependln~
on which side of the centre plane the source and observer are on.
One or both or preferably all three of reflective surfaces 20, 14 and 8 msy be tl~ted in a different colour from the tinting of surfaces
portions o~ a s:Lng1e surface.
The princlple of the invention may be understood by considerLng the paths of light beams fro~ a source S poæ:Lt:loned, for exampl.e, to the right of the centre p:Lane. I,ight beam 30 and any other light beams B from the source ~ i~pinging on reflect.lve surface 14 are reflected away from the source, as are some light beams such as light beam 31 impinging on reflective surface 12. However, light beams such as light beam 32 are reflected off ref1ective surface 12 to reflective surface 4 and thence back towards the source~ and the observer O positioned near the line of the light beam. It will be apparent that light can only be reflected back towards the source S if it reflects off both reflective surfaces 12 and 4, and not off re~lective surface 14.
Accordingly in the present lnvention one or preferably both of reflective surfaces 12 and 4 are tinted, so that light refl.ecti~g back to the source S becomes coloured. One or both of reflect.ive susfaces 8 ~` and 14 may al30 be tinted, but in a different colour so that different colours are reflected back to sources on different sides o~ the centre plane.
When the light source is positioned in the centre plane, then of course there i5 ~erely a str~ight reflection bac~ from reflectlve surfaces 12 and 14, resulting in a mixture of the tWQ colours ~eing perceived by the ob~er~er 0. However~ when the source and t-ne ob~rver move to one side or the other of the centre plane~ a coloured reflection ~ill be seen by the observar, isldicatlng which side of the plane the source and ob3erver are on.
The st~ength of the reflected signal relative to the source si~nal increases as the angle from the centse plane Lncreases, up to a ~axi~um at 45, since more of the llght re~lect~ off surface~ 12 and 4 rather : than o~f surface i2 only.
To ~inimi.ze the occurrence of excesslve internal reflection ~eyond ~' , C~7f-45 from the center plane, resulting Ln colour confuslon, the plates 2 and 4 should preEerably not extend from the plate 10 by a dLstallce greater than the cllstance between plates 2 and 6. General1y speaking, the reflector of the present invention Ls not lntended for optlmum performance beyond a 45 angle from the centre plane, although it may remain effective beyond 45 to varying degrees depending on the speciEic design.
It will be readily apparent eha~ the embodiment of Fig. 1 is only useful when the source and observer are ln the plane perpendicular to all of the reflective surfaces, i.e. in the paper plane of Fig. 1.
Otherwise, llght cannot be reflected back to the source because reElective surfaces 12 or 14 as the case may be will refLect the light upwardly or downwardly relative to the source. For many applications J
of course, this li~itation of this embodi~ent is not a problem.
In Lhe preferred e~bodi~ent, illustrated in FLg~ 2, this limitatlon is overcome by the addition of a fourth plate 16 with reflective surfaces 13 and 20. The first and second plates 2 and 6 are again parallel, plate lO i& perpendlcular to the~, and the fourth plate 16 i8 perpendicular to all three. As is well known and can be readily demonstrated, a light beam which reflects off, for example, ~urface 18 to surface 12 to surface 4 will then be reflected by surface 4 back towards the light beam source tn a manner directly analogous to that illustrated in Fig. 1. The reflector elel~ent ~s preferably oriented sueh that the source and observer are norrnally near the plane whlch is at 45 to the thlrd and fourth plates lO and 16.
Thus lf one or both or preferably all three o~ the surfaces 18, 12 and 4 are tinted, then such a light beam would produce a coloured signal to an observer positioned close to the llne of the light bea~.
In Fig. 2, the reElector element Ls ill~trated as it ~ould be seen from a viewpoint to the right of the centre plane, l.e. tha plane ~ ~'7~
parallel to and equidistant Erom reElectlve surfaces 4 and 8. It can be readily appreciated tllat some of the lLght directed towards the reflector from a source in line with the viewpoint would be reflected off surfaces 18, 12 and 4 (in any order) to produce a coLoured signal.
Part of the light would be reflected off only one or t~o of the surfaces, for example reflecting off surfaces 18 and 12 and then oEf to the left of the centre plane without contacting surface 4. None of the light which reflected off either or both of surfaces 14 and 20 would be reflected off surface 4 and back towards the source.
As Ln the case of the simple embodimetlt of Fig. 1, when the light source is positioned in the centre plane, there is simple reElection back towards the source, off suriaces 18 and 12 and off surfaces ~0 and 14, resultin~ in a mi~ture of colours being perceived. Mowever, moving the source and the observer away from the centre plane results in different coloured signals being retur~ed to the observer dependln~
on which side of the centre plane the source and observer are on.
One or both or preferably all three of reflective surfaces 20, 14 and 8 msy be tl~ted in a different colour from the tinting of surfaces
4, 12 and/or 18, or surfaces 2~ 14, 8 may be lPft untinted.
?O A number of variations on the invention are obvious and are ~ithin the scope of the invention. For example, the shape and ~cructure of ; the reflector may be ~aried as desired as long as the essential re1ationship of reflective surfaces is ~mchanged~ S$mllarly, the size of the reflector unit is immaterial; ~here may be one or more large reflector units, or a large number of very small reflector units -Ln an array, as desired for the particular application.
Any known and suitable reflective material or coatin~ and tinting means may be employed.
:
:
It Ls also obvLous that the reflector unLt has appllcatlon not only in indicatlng the position of an observer and llght source ln relatlon to a statlonary reflector, but also Ln indlcating the angular orlentatlon of a movlng reflector unLt in relation to a fixed observer and ]ight source, or for that matter in relation to an also-moving observer and llght source.
In most applications, the centre plane will be vertical, but it i9 obvious that the reflector element could be positioned so that the centre plane Ls horizontal or at any desired angle to the horlzontal, as for e~ample to indicate an optimum alrcraft landing glide slope.
~0
?O A number of variations on the invention are obvious and are ~ithin the scope of the invention. For example, the shape and ~cructure of ; the reflector may be ~aried as desired as long as the essential re1ationship of reflective surfaces is ~mchanged~ S$mllarly, the size of the reflector unit is immaterial; ~here may be one or more large reflector units, or a large number of very small reflector units -Ln an array, as desired for the particular application.
Any known and suitable reflective material or coatin~ and tinting means may be employed.
:
:
It Ls also obvLous that the reflector unLt has appllcatlon not only in indicatlng the position of an observer and llght source ln relatlon to a statlonary reflector, but also Ln indlcating the angular orlentatlon of a movlng reflector unLt in relation to a fixed observer and ]ight source, or for that matter in relation to an also-moving observer and llght source.
In most applications, the centre plane will be vertical, but it i9 obvious that the reflector element could be positioned so that the centre plane Ls horizontal or at any desired angle to the horlzontal, as for e~ample to indicate an optimum alrcraft landing glide slope.
~0
Claims (5)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A reflector element comprising first and second reflective surfaces facing each other equidistant from and parallel to an imaginary centre plane, and a third reflective surface adjacent to and abutting perpendicularly said first and second reflective surfaces, in which at least one reflective surface is tinted on one side of the centre plane.
2. A reflector element as recited in claim 1, further comprising a fourth reflective surface adjacent to and abutting perpendicularly said first, second and third reflective surfaces.
3. A reflector element as recited in claims 1 or 2, in which all of the reflective surfaces on the one side of the centre plane are identically tinted.
4. A reflector element as recited in claims 1 or 2 in which at least one reflective surface is tinted on the other side of the centre plane, the color of the tinting on the one side of the centre plane being different from the colour of the tinting on the other side.
5. A reflector element as recited in claims 1 or 2, in which all of the reflective surfaces are tinted, the colour of the tinting on one side of the centre plane being different from the colour of the tinting on the other side of the centre plane.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000419300A CA1227075A (en) | 1983-01-12 | 1983-01-12 | Colour varying reflector |
| US06/570,191 US4560236A (en) | 1983-01-12 | 1984-01-12 | Color varying reflector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000419300A CA1227075A (en) | 1983-01-12 | 1983-01-12 | Colour varying reflector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1227075A true CA1227075A (en) | 1987-09-22 |
Family
ID=4124324
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000419300A Expired CA1227075A (en) | 1983-01-12 | 1983-01-12 | Colour varying reflector |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4560236A (en) |
| CA (1) | CA1227075A (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4930870A (en) * | 1987-07-27 | 1990-06-05 | Itw New Zealand Limited | Retro-reflectors |
| US5022739A (en) * | 1990-06-13 | 1991-06-11 | Bennett Reginald B | Direction indicating reflector with planar reflector panels including cube corners |
| US5237449A (en) * | 1991-01-29 | 1993-08-17 | Nelson Optics Company, Inc. | Biased lenticular sign system |
| US5175645A (en) * | 1991-12-04 | 1992-12-29 | Bennett Reginald B | Three panel reflector |
| US5619346A (en) * | 1995-08-28 | 1997-04-08 | Xerox Corporation | Method and system for converting a half rate/full rate monochrome scanner to a half rate/full rate color scanner |
| JP4604801B2 (en) * | 2004-12-27 | 2011-01-05 | 三菱電機株式会社 | Planar light source device and display device using the same |
| CN100526929C (en) * | 2005-04-29 | 2009-08-12 | 皇家飞利浦电子股份有限公司 | Compact stepping lens actuator for mobile cameras |
| DE202006013194U1 (en) * | 2006-08-28 | 2006-11-09 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Light module has a light source and a reflector having a colored eloxal layer spectral filter on its upper side |
| TWM335621U (en) * | 2008-01-24 | 2008-07-01 | Licht Co Ltd De | Desk lamp |
| JP5433288B2 (en) * | 2009-04-15 | 2014-03-05 | 株式会社津村総合研究所 | Aircraft landing gear |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3374044A (en) * | 1964-11-03 | 1968-03-19 | Gen Dynamics Corp | Filtered wave-energy corner-reflector |
-
1983
- 1983-01-12 CA CA000419300A patent/CA1227075A/en not_active Expired
-
1984
- 1984-01-12 US US06/570,191 patent/US4560236A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| US4560236A (en) | 1985-12-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |